$ echo -e '{|\n| style="background: <nowiki>\n\n\n\nred;</nowiki>" | hi\n|}' | php maintenance/parse.php 
<table>
<tr>
<td style="background: red;"> hi
</td></tr></table>

and

$ echo -e '{|\n| style="background: <nowiki>\n\n\n\nred;</nowiki>" | hi\n|}' | tests/parse.js  --normalize

<table>
<tbody>
<tr>
<td style="background: 



red;">hi</td>
</tr>
</tbody>
</table>

(note that the PHP sanitizer is removing the newlines, but that's not important)

But this breaks if the content is template affected. As arlo found:

(04:19:43 PM) arlolra: ah, i think i see what's going on
(04:19:44 PM) arlolra: https://github.com/wikimedia/parsoid/blob/master/lib/dom.t.TableFixups.js#L188-L190
(04:19:49 PM) arlolra: is just taking content
(04:20:08 PM) arlolra: and then reparsing it fails
(04:20:08 PM) arlolra: https://github.com/wikimedia/parsoid/blob/master/lib/dom.t.TableFixups.js#L267-L268
(04:20:12 PM) arlolra: from the newline

This is hard to demonstrate from the command-line, since you can't really coerce {{echo}} to emit a vertical bar in an appropriate way (if you use {{!}} inside echo it in effect gets interpreted *before* the arguments are passed to echo, so it separates the arguments to echo instead of being passed through to echo's output).

But parser tests will work:

!! article
Template:styletest
!! text
style="background: <nowiki>


red;</nowiki>" |
!! endarticle

!! test
T107622
!! wikitext
{|
| {{styletest}} hi
|}
!! html/php
<table>
<tr>
<td style="background: red;"> hi
</td></tr></table>
!! html/parsoid
<table>
<tbody>
<tr>
<td><span typeof="mw:Transclusion" data-mw='{"parts":[{"template":{"target":{"wt":"styletest","href":"./Template:Styletest"},"params":{},"i":0}}]}'>style="background: </span><span typeof="mw:Nowiki"> red;</span><span>" |</span> hi</td>
</tr>
</tbody>
</table>
!! end

Note the buggy html/parsoid output.

Note that the vertical bar needs to be inside the template to trigger the dom.t.TableFixups.js code, and thus the bug.